Field of the Invention
The present disclosure relates to a prismatic secondary battery and an assembled battery using the prismatic secondary battery.
Description of Related Art
In drive power supplies of electric vehicles (EV) and hybrid electric vehicles (HEV, PHEV), a secondary battery such as an alkaline secondary battery or a nonaqueous electrolyte secondary battery is used. For these applications, high capacity or high output characteristics is demanded, and thus an assembled battery is used in which a large number of prismatic secondary batteries are connected in series or in parallel.
In those prismatic secondary batteries, a battery case is formed by a bottomed tubular prismatic outer body having an opening, and a sealing plate that seals the opening. An electrode body including a positive electrode plate, a negative electrode plate, and a separator is housed in the battery case along with an electrolytic solution. A positive electrode terminal and a negative electrode terminal are fixed to the sealing plate. The positive electrode terminal is electrically connected to the positive electrode plate via a positive electrode current collector, and the negative electrode terminal is electrically connected to the negative electrode plate via a negative electrode current collector.
The positive electrode plate includes a positive electrode core made of metal, and a positive electrode active material layer formed on the surface of the positive electrode core. In part of the positive electrode core, a positive electrode core exposed portion is formed in which a positive electrode active material layer is not formed. The positive electrode current collector is then connected to the positive electrode core exposed portion. Also, the negative electrode plate includes a negative electrode core made of metal, and a negative electrode active material layer formed on the surface of the negative electrode core. In part of the negative electrode core, a negative electrode core exposed portion is formed in which a negative electrode active material layer is not formed. The negative electrode current collector is then connected to the negative electrode core exposed portion.
For instance, Japanese Published Unexamined Patent Application No. 2009-032640 (Patent Document 1) proposes a prismatic secondary battery using a winding electrode body which has a positive electrode core exposed portion wound at one end and a negative electrode core exposed portion wound at the other end. Also, Japanese Published Unexamined Patent Application No. 2008-226625 (Patent Document 2) proposes a prismatic secondary battery using a winding electrode body which is provided with a positive electrode core exposed portion and a negative electrode core exposed portion at one end.